Hard core DIY'er here, but not as savvy with complex home electrical yet. I'm pretty good with most electrical, but before I burn the house down, need someone more qualified to look over my diagram and see if I'm right or provide the right guidance. This is on a rental property I own and it had some electrical work done in the past (not me). Have been doing some minor touch-ups after a prior tenant moved out and getting ready for a new tenant. Found that the under sink electrical isn't working the way it had before; the switched garbage disposal doesn't work as the GFCI does not show power to it, but the dishwasher works without any issues. After killing the power and opening the box, found some wires disconnected. Now trying to piece the puzzle back together.
Schematic here: https://drive.google.com/file/d/1nO9GnTzDV6z_kjj0gJefYDz3NBoFuVB7/view?usp=sharing

Thanks to input provided, revised the diagram. Plan to go hard-wired disposer as advised vs. plug in. Might have been part of the problem why someone was messing with it in the first place. Another review requested to ensure I have it all connected right. This is more of an education lesson for me vs. me doing the actual work unsupervised.

Revision 1 schematic here: https://drive.google.com/file/d/1itj2s25zAN7KRJWoIZmeFH3x90eez0R7/view?usp=sharing

  • 2
    We're not the 'work on your house' police but do note that doing any electrical work on a property you don't live without a permit in is illegal most places, especially if it's a rental property. Just so long as you know what rule you're breaking.
    – KMJ
    Nov 21, 2023 at 18:18
  • New diagram looks correct. Nov 21, 2023 at 20:16
  • Appreciate the comment. Haven't broken any rules yet and not intending to. I want a plan so when I get the work accomplished (or have the licensed sparky watch me do it) everyone is on the same page. Knowledge is power and the more I learn, the more I know where I might be over my head.
    – TechGuy
    Nov 21, 2023 at 20:17
  • 1
    That's helpful advice there.
    – TechGuy
    Nov 21, 2023 at 20:26
  • 1
    Great advice - they can check over the simple stuff you did in a few minutes after they do the more complicated stuff.
    – KMJ
    Nov 21, 2023 at 22:06

1 Answer 1


Basically it looks like someone replaced a standard duplex receptacle that had the hot-side tab removed so it could operate half-switched (for disposal) with a GFCI. And had no idea what they were doing.

A GFCI/receptacle is a good idea (required in recent code, but not nearly as long as countertop receptacles) for dishwasher and disposal. But you can't quite get there from here, because a GFCI/receptacle can't be "half switched".

My recommendation is to change to all GFCI protected, but that requires changing the disposal to hardwired, which most disposals can do:

  • Figure out which (top or bottom) is "LINE" (as opposed to "LOAD") on the GFCI.
  • Line in black hot -> GFCI LINE hot
  • Line in white neutral -> GFCI LINE neutral
  • GFCI LOAD hot -> switch white wire with black tape and dishwasher black hot
  • GFCI LOAD neutral -> disposal white neutral and dishwasher white neutral
  • Switch black switched hot -> disposal black switched hot

The GFCI may allow two wires on each terminal (screw-to-clamp) or may not. If it does not then you will need to use pigtails and wire nuts.

You will need replace the disposal plug/cord with a cable (e.g., Romex non-metallic cable). In the box with the GFCI/receptacle, you will connect it to the switch black wire and to the GFCI LOAD neutral.

A couple of possible issues:

  • Generally anything but the most basic electric work in a rental is supposed to be done by an electrician. This was clearly not done by an electrician previously (probably a tenant who was trying to fix something and just made a mess but didn't want to tell you because then they'd be in trouble, so they lived without a working disposal for a while) and the fix is more complicated than a straight switch or receptacle replacement.
  • Since I suspect the receptacle was originally a plain receptacle, it may already be in an overcrowded box and doing all this could get tricky and possibly against code, depending on the size of the box.

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